Body effects on the GPS antenna of a wearable tracking device

The performance of a GPS antenna (inverted-F) design is investigated when the tracking device is placed on flat torso and dog-shaped phantoms. A prototype of the device is constructed to validate the proposed antenna design in free space condition with both measurement and simulation. Following that, the effects of body loading to the antenna are examined through numerical simulations to achieve an optimum orientation of the device with respect to the actual operating condition (with body loading). The results from this study indicate that the radiation/reception characteristics of a small GPS antenna can be very different between free space and body loading conditions. In order to achieve the best antenna performance, the body loading effect should be closely examined.